Why Do Japanese Children Who Stutter Find It Difficult to Pronounce Vowels?

—Focus on Initial Mora Frequency—

Abstract

The purpose of the present study was to investigate the effect of consonants and vowels on the occurrence of stuttering and the relationships between initial mora frequency and the amount of stuttering among Japanese school-age children who stutter (CWS). The final aim was to determine why Japanese CWS find it difficult to pronounce words beginning with vowels. The participants were 20 Japanese CWS aged 6 to 12 years. Free conversations between the participants and the author were recorded, and their speech was analyzed. Binomial logistic regression revealed that consonant-vowel difference had no significant impact on the occurrence of stuttering. In addition, certain vowels (/i/, /o/, and /a/) had a higher initial mora frequency than consonants. Furthermore, the amount of stuttering of those vowels is also greater than that of consonants. Taken together, we speculate that Japanese CWS find it difficult to pronounce words that begin with certain vowels because these vowels are more likely to appear at the beginning of a "bunsetsu" (a kind of Japanese linguistic unit), and the number of occurrences of stuttering was also higher with these vowels.